CSP for NeoMagic.css: Lock It Down Without Breaking Styles

NeoMagic.css is the kind of CSS framework people pick because they want speed, tiny bundles, and fewer moving parts. Good call. But once you start shipping a real app with analytics, fonts, icons, and maybe a little JavaScript sugar, your CSP usually turns into a weird mix of good intentions and emergency exceptions.

I’ve seen this a lot: the app starts with a nice strict policy, then somebody adds a tag manager, then a consent banner, then inline styles sneak in, and now style-src 'unsafe-inline' is hanging around forever like a bad temporary fix.

If you’re using NeoMagic.css, the good news is that CSS-first sites are usually easier to protect with CSP than heavy JavaScript apps. Less script execution means fewer headaches. The trick is staying disciplined.

What NeoMagic.css changes about CSP

NeoMagic.css itself doesn’t magically require a loose policy. It’s just CSS. That means your main CSP concerns are usually:

loading the stylesheet itself
handling any inline <style> blocks
allowing fonts and images used by the theme
dealing with JavaScript you add around it
avoiding unsafe-inline and unsafe-eval unless you absolutely have to

For most NeoMagic.css sites, these directives matter most:

default-src
style-src
script-src
font-src
img-src
connect-src
frame-src
base-uri
form-action
object-src
frame-ancestors

If you want a deeper refresher on what each directive does, csp-guide.com is a solid reference.

Start with a strict baseline

Here’s a good baseline CSP for a self-hosted NeoMagic.css site with no third-party junk:

Content-Security-Policy:
  default-src 'self';
  script-src 'self';
  style-src 'self';
  img-src 'self' data:;
  font-src 'self';
  connect-src 'self';
  object-src 'none';
  base-uri 'self';
  form-action 'self';
  frame-ancestors 'none';

This is a strong starting point because it assumes:

NeoMagic.css is served from your own origin
your JS is served locally
images are local or embedded as data:
fonts are local
no iframes, embeds, or plugins

For a lot of marketing sites or docs pages, this is enough.

A minimal HTML example

Here’s a simple NeoMagic.css page that works with that baseline:

<!doctype html>
<html lang="en">
<head>
  <meta charset="utf-8">
  <title>NeoMagic Demo</title>
  <link rel="stylesheet" href="/css/neomagic.min.css">
  <link rel="stylesheet" href="/css/app.css">
</head>
<body>
  <main class="container">
    <h1 class="hero-title">Hello NeoMagic</h1>
    <p class="text-muted">Styled without weakening CSP.</p>
    <img src="/img/logo.png" alt="Logo">
  </main>

  <script src="/js/app.js" defer></script>
</body>
</html>

Nothing special here, and that’s the point. CSP gets much easier when you keep assets external.

The first place people mess up: inline styles

A lot of frontend teams will drop in stuff like this:

<div style="margin-top: 2rem; color: rebeccapurple;">
  Welcome
</div>

Or:

<style>
  .hero-title {
    text-shadow: 2px 2px #000;
  }
</style>

That pushes you toward:

style-src 'self' 'unsafe-inline';

That works, but I try hard to avoid it. unsafe-inline for styles is less catastrophic than for scripts, but it still weakens the policy and makes it easier for style injection bugs to become useful.

Better approach: move styles into static CSS files.

.welcome-banner {
  margin-top: 2rem;
  color: rebeccapurple;
}

.hero-title {
  text-shadow: 2px 2px #000;
}

Then:

<div class="welcome-banner">Welcome</div>

If you control the codebase, this is the cleanup worth doing.

When inline styles are unavoidable

Sometimes you really do need inline styles. Maybe NeoMagic.css is being used inside a CMS, or you generate critical CSS server-side. In that case, you’ve got two choices:

allow 'unsafe-inline' in style-src
use a hash or nonce-based approach where supported

For many teams, style nonces are more annoying operationally than they’re worth unless the app already has a nonce pipeline for scripts.

Example with a nonce:

Content-Security-Policy:
  default-src 'self';
  script-src 'self' 'nonce-r4nd0m123';
  style-src 'self' 'nonce-r4nd0m123';
  img-src 'self' data:;
  font-src 'self';
  object-src 'none';
  base-uri 'self';
  form-action 'self';
  frame-ancestors 'none';

And HTML:

<head>
  <link rel="stylesheet" href="/css/neomagic.min.css">
  <style nonce="r4nd0m123">
    .theme-accent { color: #7c3aed; }
  </style>
</head>

Your nonce must be generated per response, not hardcoded. If it’s static, you’ve defeated the point.

Express example with per-request nonce

Here’s a practical Express setup:

import express from "express";
import crypto from "crypto";

const app = express();

app.use((req, res, next) => {
  res.locals.nonce = crypto.randomBytes(16).toString("base64");
  next();
});

app.use((req, res, next) => {
  const nonce = res.locals.nonce;

  res.setHeader(
    "Content-Security-Policy",
    [
      "default-src 'self'",
      `script-src 'self' 'nonce-${nonce}'`,
      `style-src 'self' 'nonce-${nonce}'`,
      "img-src 'self' data:",
      "font-src 'self'",
      "connect-src 'self'",
      "object-src 'none'",
      "base-uri 'self'",
      "form-action 'self'",
      "frame-ancestors 'none'"
    ].join("; ")
  );

  next();
});

app.get("/", (req, res) => {
  const nonce = res.locals.nonce;

  res.send(`
    <!doctype html>
    <html>
      <head>
        <link rel="stylesheet" href="/css/neomagic.min.css">
        <style nonce="${nonce}">
          .hero-title { color: mediumspringgreen; }
        </style>
      </head>
      <body>
        <h1 class="hero-title">NeoMagic + CSP</h1>
        <script nonce="${nonce}">
          console.log("Inline script allowed by nonce");
        </script>
      </body>
    </html>
  `);
});

app.listen(3000);

That’s a clean pattern when you really need inline code.

Third-party services are where clean CSPs go to die. You add one script, it loads another script, then opens connections to three extra origins, then injects styles.

Here’s a real-world CSP header from headertest.com:

content-security-policy: default-src 'self' https://www.googletagmanager.com https://*.cookiebot.com https://*.google-analytics.com; script-src 'self' 'nonce-MTc4ZDZmODQtYjk2ZS00YjU3LTlhMWItM2EzYTExNTNmNGM3' 'strict-dynamic' https://www.googletagmanager.com https://*.cookiebot.com https://*.google-analytics.com; style-src 'self' 'unsafe-inline' https://www.googletagmanager.com https://*.cookiebot.com https://consent.cookiebot.com; img-src 'self' data: https:; font-src 'self'; connect-src 'self' https://api.headertest.com https://tallycdn.com https://or.headertest.com wss://or.headertest.com https://*.google-analytics.com https://*.googletagmanager.com https://*.cookiebot.com; frame-src 'self' https://consentcdn.cookiebot.com; frame-ancestors 'none'; base-uri 'self'; form-action 'self'; object-src 'none'

There’s a lot going on there, but a few things stand out:

script-src uses a nonce and 'strict-dynamic'
style-src still needs 'unsafe-inline'
connect-src is expanded for APIs, analytics, and WebSockets
frame-src allows the consent provider
object-src 'none' and frame-ancestors 'none' are still locked down

That’s a realistic production policy. Not perfect, but grounded in how modern services actually behave.

A practical NeoMagic.css policy with common extras

If your NeoMagic.css app uses self-hosted CSS, a CDN font, analytics, and an API, you might end up with something like this:

Content-Security-Policy:
  default-src 'self';
  script-src 'self' 'nonce-{{NONCE}}' 'strict-dynamic';
  style-src 'self' https://fonts.googleapis.com;
  font-src 'self' https://fonts.gstatic.com;
  img-src 'self' data: https:;
  connect-src 'self' https://api.example.com https://www.google-analytics.com;
  frame-src 'self';
  object-src 'none';
  base-uri 'self';
  form-action 'self';
  frame-ancestors 'none';

A couple of opinions here:

self-host fonts if you can
don’t add domains to default-src unless you truly want them broadly allowed
prefer specific directives over bloating default-src
use nonces for scripts if any inline bootstrapping exists

Nginx example

If you’re serving a static NeoMagic.css site with Nginx:

add_header Content-Security-Policy "
  default-src 'self';
  script-src 'self';
  style-src 'self';
  img-src 'self' data:;
  font-src 'self';
  connect-src 'self';
  object-src 'none';
  base-uri 'self';
  form-action 'self';
  frame-ancestors 'none';
" always;

For static sites, this is usually all you need. If you later bolt on third-party services, update only the directives that actually need expansion.

Debugging CSP breakage

When NeoMagic.css pages break under CSP, it’s usually one of these:

1. Styles not applying

Check for:

inline <style>
style="" attributes
CSS loaded from a CDN you forgot to allow

Browser console error example:

Refused to apply inline style because it violates the following Content Security Policy directive: "style-src 'self'".

2. Icons or fonts missing

If NeoMagic.css theme assets use webfonts, you may need:

font-src 'self' https://fonts.gstatic.com;

3. Background images blocked

If CSS references external images, you may need:

img-src 'self' data: https:;

4. JS-enhanced components failing

That’s usually script-src or connect-src. If a component fetches remote JSON:

connect-src 'self' https://api.example.com;

Use Report-Only before enforcing

When tightening a policy on an existing site, I start with Content-Security-Policy-Report-Only so I can collect violations without breaking production.

Example:

Content-Security-Policy-Report-Only:
  default-src 'self';
  script-src 'self';
  style-src 'self';
  img-src 'self' data:;
  font-src 'self';
  connect-src 'self';
  object-src 'none';
  base-uri 'self';
  form-action 'self';
  frame-ancestors 'none';

Roll it out, watch the console and reports, fix violations, then switch to enforcement.

My default recommendation for NeoMagic.css

If I were setting this up from scratch, I’d do this:

self-host NeoMagic.css
keep all styles in external CSS files
avoid inline scripts and styles
use a nonce if inline code is unavoidable
self-host fonts and icons where possible
start with a strict baseline and add exceptions one by one
never paste a giant CSP from another site without understanding every origin in it

A CSS-first stack like NeoMagic.css gives you a real advantage here. You don’t need a giant permissive policy. Most of the time, a small, boring CSP is the right one. That’s what you want. Boring security settings usually age better than clever ones.

What NeoMagic.css changes about CSP#

Start with a strict baseline#

A minimal HTML example#

The first place people mess up: inline styles#

When inline styles are unavoidable#

Express example with per-request nonce#

If you add analytics or consent tools, copy less and think more#

A practical NeoMagic.css policy with common extras#

Nginx example#

Debugging CSP breakage#

1. Styles not applying#

2. Icons or fonts missing#

3. Background images blocked#

4. JS-enhanced components failing#

Use Report-Only before enforcing#

My default recommendation for NeoMagic.css#